Dr. Tennant is board certified in ophthalmology and ophthalmic plastic surgery (residency, Harvard Medical School & Southwestern Medical school) He was the director of the ophthalmic plastic surgery clinic at Parkland Hospital and practiced from 1965 to 1995. He did much of the FDA study for the VISX Excimer laser, and he performed approximately 1000 surgeries in the United States and Europe. He was the founder/director of the Dallas Eye Institute and was one of the first surgeons in the US to place intraocular lenses in eyes after cataract surgery. He taught these techniques around the world. He holds patents for medical devices, including intraocular lenses and several surgical instruments.